1. Field of the Invention
This invention relates to connectors and more particularly to electrical connectors used in moisture-laden environments.
2. Description of the Related Art
In seismic exploration, as well as in other types of industry, it is sometimes necessary to make and maintain electrical connections in moisture-laden environments. The amounts of moisture may range from a very humid laboratory chamber to the bottom of the ocean. For obvious reasons, the most important characteristic about the type of electrical connector used is that it maintain a watertight seal. A connector that allows the smallest amount of moisture past its barriers may prove to be nearly if not completely fatal. For example, in seismic surveys across marshy or swamp-like environments, a leaky connector may be responsible for an inoperative array of 1000 or more sensors.
In general there are many different types of watertight electrical connectors, but all of them have at least two characteristics in common: at least one cable entering the connector body, and at least one end designed to mate with a similar connector. Both of the characteristics mentioned above are perhaps responsible for a clear majority of connector failures. A myriad of connectors have been introduced to solve water leakage along the connector face. A typical connector of this type is disclosed in U.S. Pat. No. 4,445,741 issued I. R. Annoot in May, 1984. Many of these connectors have proven to be successful at keeping water out of the connector face.
A majority of electrical connectors suffer signal loss because of decreased resistance and consequent electrical leakage due to water wicking along the stranded conductor cable from the rear of the connector. The stranded electrical conductors of the cable are often enclosed in a molded, polyurethane connector body and have no other barrier to prevent water leakage other than the molded jacket. This type of barrier often fails when a tensional force is introduced between the cable and the connector body. The tension causes a necking down of the cable, providing a greater passage for the moisture to enter. Occassionally, tension along the cable also results in the tension being applied to the electrical conductors and breaks the connection thereto.
Several different techniques have been implemented to prevent moisture from reaching the exposed conductors. One such technique involved a rubber washer or grommet compressed around the conductor cable at the entrance to the connector by way of a gland nut. It was also suggested that the seal be anchored to the cable within the housing. In a variation of the above technique, a plurality of seals in series compressed by a single gland nut were to provide protection, however each of the above techniques failed under normal use. A successful method involved a connector having a design that clamped to the conductor cable well ahead of the seals to prevent necking down of the cable. A disadvantage to this method is the elaborate construction and the cost ineffectiveness.